Have any of you heard of this crazy new rule from January 2019?

So we hired an audit firm to look at our coding and OASIS in preparation for PDGM. Actually, we have two companies looking at our documentation. One of them says to only code pertinent conditions--what we are currently treating and any conditions that may impact the plan of care or response to treatment. The second one brought to our attention a CMS transmittal from Jan 23 2019. It's a HHA FAQ list. One of them says this:
Q:Must "all diagnoses" be documented on the comprehensive assessment? A:All pertinent diagnoses must be included on the plan of care. "All pertinent diagnoses" means all known diagnoses

So they were coding every diagnosis documented by a physician. I have never seen this mentioned anywhere--not Diagnosis Coding Pro or anything else. Did I miss something?